1. Field of the Invention
The invention relates to an apparatus for delivering portions of uniform weight and/or volume of a pasty substance, particularly sausage stuffing, the apparatus comprising a conveying mechanism, which includes a rotor, driven to rotate about an axis of rotation, and a casing, designed with at least one supply and one discharge opening, each, said rotor comprising a stationary control cam designed with a discharge motion controlling section; a plurality of portion chambers for receiving the substance to be delivered; and a corresponding number of displacer pistons arranged in the portion chambers to be displaced therein during the rotation of the rotor by operatively engaging said cam, the displacement being such that, over a complete rotation of said rotor, proportionality is obtained between the discharge of the substance and the angle of rotation of the rotor.
2. Prior Art
An apparatus of this type is known from DE-OS No. 34 09 517. The conveying mechanism for pasty substances disclosed therein has the features of a radial piston pump. Therein the radial displacement motion of the displacer pistons takes place by a fixed control cam, against which the displacer pistons support during the rotation of the rotor receiving the pistons. In accordance with the position of the discharge opening of the casing, the arrangement of the displacer pistons, as well as the association of the section of the control cam responsible for the portioning stroke of the displacer pistons, is such that the discharge motion of anyone of them starts at the instant at which the preceding one has ended its discharge movement. With respect to the objective of achieving proportionality between the conveying volume and the angle of rotation of the rotor, both for the start of the discharge motion of a displacer piston and for the end of the discharge motion of the preceding piston, there are theoretically infinitely high acceleration values on the pistons. Due to the elasticity of the system these values are, of course, not reached in practice, but they are, nevertheless, sufficiently high for the known conveying mechanism to run in an extremely rough manner. This leads to an unpleasant evolution of noise and to above-average wear. Moreover, the differences in the motions occurring in practice compared with the theoretical values cause fluctuations in the dosing accuracy.
3. Objects of the Invention
It is therefore an essential object of the present invention to suggest a rotary conveying mechanism having conveying characteristics proportional to the angle of rotation. It is a further major object to suggest such a mechanism which runs smoothly and therefore at low noise and with little wear.